US secretary of state Hillary Clinton has a blood clot between her brain and skull, but she is expected to make a full recovery, her doctors say.

Yesterday Ms Clinton was admitted to a New York hospital after doctors discovered a blood clot, stemming from a concussion she received last month.

A subsequent scan revealed "a clot in the vein that is situated in the space between the brain and the skull behind the right ear. It did not result in a stroke, or neurological damage," the doctors said in a statement this morning.

They said Ms Clinton was "making excellent progress and we are confident she will make a full recovery."

"She is in good spirits, engaging with her doctors, her family, and her staff," they added in the statement.

Ms Clinton's top aide, Philippe Reines, said on Sunday the popular US secretary of state would stay in the hospital for some 48 hours so she could be monitored while on anti-coagulant drugs.

In December the 65-year-old contracted a bad stomach virus during a five-day stay in Europe.

She had to cancel a planned trip to North Africa and Abu Dhabi due to the illness.

Ms Clinton previously had a blood clot in her leg in 1998 while she was first lady in the White House of her husband and then-president Bill Clinton.

She described the previous clot as the "most significant health scare" she had ever had.

"That was scary because you have to treat it immediately - you don't want to take the risk that it will break loose and travel to your brain or your heart or your lungs," she told the New York Daily News in October 2007.

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